Implantable neuro-stimulation systems have proven therapeutic in a wide variety of disorders e.g., Parkinson's disease, chronic neuropathic pain, or the like. For example, spinal cord stimulation systems have been used as a therapeutic modality for the treatment of chronic pain syndromes. Deep brain stimulation has also been useful for treating refractory chronic pain syndromes and has been applied to treat movement disorders and epilepsy. Peripheral nerve stimulation has been used to treat chronic pain syndrome and incontinence. Functional electrical stimulation systems have been applied to restore some functionality to paralyzed extremities in spinal cord injury patients. Additionally, sacral nerve stimulation is a promising option for patients suffering from pelvic floor disorders such as, for example, urinary incontinence, fecal incontinence, over active bladder (OAB), dual incontinence, severe constipation, or the like.
OAB is a condition often characterized by a strong urge to urinate and/or a need to urinate more often than normal. Often times, OAB occurs in patients when signals transmitted from a patient's brain to their bladder instruct the bladder to empty even when it isn't full. OAB may also occur when the muscles in a patient's bladder are too active, thereby causing more frequent evacuation. In some patients, OAB may be paired with involuntary leakage of urine from the bladder. Fecal incontinence is a condition often characterized by the inability to control bowel movements causing stool to leak unexpectedly from the rectum. In many cases, patients may suffer from both OAB and fecal incontinence, a condition referred to as dual incontinence. Patients suffering from severe constipation, including those with slow transit and others with normal transit but having impaired evacuation, often find little to no relief with conventional pharmacological and behavioral treatments.
Pelvic floor disorders may be associated with improper sacral nerve functioning which influences the operation of related organs, e.g., the bladder and large bowel (large intestine). One treatment option for such disorders is sacral nerve stimulation. Sacral nerves can be electrically stimulated to control the functioning of the bladder and/or the large bowel. The sacral nerve may be stimulated by an implantable stimulation system. The implantable sacral nerve stimulation system typically includes an implantable pulse generator and an implantable lead. The lead may include electrodes that may be positioned proximate the sacral nerve to deliver electrical pulses generated by the implantable pulse generator to the sacral nerve. However, certain challenges are associated with sacral nerve stimulation such as, for example, migration of the lead which may result in ineffective delivery of therapy.
To overcome lead migration, leads may be fixed to desired locations for stimulation. Lead fixation enables the lead to be held in place at least until the scar tissue grows around the lead. Current methods of lead fixation include the use of sutures, fixation tines, or a lead anchor device such as the “Clik Anchor” sold by Boston Scientific, Inc., or the “Cinch Anchor” or “Swift-Lock Anchor” sold by St. Jude Medical, Inc. These lead anchors, however, are too bulky to be used in Sacral Nerve Stimulation procedures. They also introduce more foreign body material into the patient resulting in an increased foreign body response and therefore increased inflammatory response. Fixation of the lead with a device or suture adds time to the operation and requires a skilled surgeon. While adhesives may be used, current implantable adhesives provide a poor or incomplete bond with low strength. Those adhesives with high fixation strength are toxic and typically only used externally. Hence, there remains a need for a lead fixation technique that is both effective, easy to deploy, and robust while causing minimal tissue damage.